PATHOLOGY

Detailed explanation-1: -T lymphocytes develop from a common lymphoid progenitor in the bone marrow that also gives rise to B lymphocytes, but those progeny destined to give rise to T cells leave the bone marrow and migrate to the thymus (see Fig. 7.2). This is the reason they are called thymus-dependent (T) lymphocytes or T cells.

Detailed explanation-2: -T lymphocytes originate from bone marrow progenitors that migrate to the thymus for maturation, selection, and subsequent export to the periphery.

Detailed explanation-3: -B-cells and T-cells are the two main types of lymphocytes. There are primary and secondary organs involved in the complex development of lymphocytes, but in most cases, B-and T-lymphocytes are generated in bone marrow and in the thymus.

Detailed explanation-4: -T cells represent about 3–8% of total nucleated BM cells, and have a typically reduced CD4/CD8 T cell ratio, as compared with blood (1, 2).

Detailed explanation-5: -T cells originate in the bone marrow and mature in the thymus. In the thymus, T cells multiply and differentiate into helper, regulatory, or cytotoxic T cells or become memory T cells.